Discovered my 1999 email address in my archives. I can see my old account in the User Search section so it is there. Going to the http://setiathome.berkeley.edu/sah_email_form.php link, it seems that my classic password is essential to completing the migration.
Should be able to link without the Classic password?

You don't need your SETI Classic password to link your old SETI account to your new BOINC-SETI account. Simply use the link that BilBg gave in this thread and it should guide you through the linking process.